CODEWITHSUNDEEP
iosarraysswiftshuffleswift-playground
Ilir V. Gruda
Ilir V. Gruda

Reputation: 1572

Shuffle function is not being implemented correctly in Swift 1.2

I have a function, which is used to shuffle an array. This function is working fine in playground but when I am trying to implement it on my project I am having an error.

Here is the code:

import UIKit
import Darwin

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    func shuffle<C: MutableCollectionType where C.Index.Distance == Int>(var list: C) -> C {
        var n = count(list)
        if n == 0 { return list }
        let oneBeforeEnd = advance(list.startIndex, n.predecessor())
        for i in list.startIndex..<oneBeforeEnd {
            let ran = Int(arc4random_uniform(UInt32(n--)))
            let j = advance(i,ran)
            swap(&list[i], &list[j])
        }
        return list
    }

    var numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

    shuffle(numbers)


}

The error is occurring when I am calling shuffle() saying expected declaration. Can anyone tell me where should I add the function or should I do something to implement correctly this code.

Upvotes: 0

Views: 86

Answers (1)

luk2302
luk2302

Reputation: 57124

You have to move the call of shuffle to the body of any method. For example viewDidLoad. You either have to move the declaration and definition of the numbers to there too - or at least move it to the start of the class declaration:

class ViewController: UIViewController {
    var numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] // either have the var decl here

    override func viewDidLoad() {
        super.viewDidLoad()

        var numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] // or here
        shuffle(numbers)
    }

    ...

    func shuffle<C: MutableCollectionType where C.Index.Distance == Int>(var list: C) -> C {
        ...
    }
}

Upvotes: 1

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